Distillation system



May 5, 1931. A. F. KEANE ,803,671

nIsTIL A rIoN SYSTEI Filed April 17. 1926 5 Sheets-Sheet l A TTOR/VE 78 y A. F. KEANE 1,803,671

DISTILLATION SYSTEM Filed April 17, 1926 s Sheets-Sheet 2 W/T/VESS A TTORNEY y 5, 1931- A. F. KEANE 1,803,671

' DISTILLATION SYSTEM Filed April 17, 1926 5 Sheets-Sheet 4 45 WITNESS E/VTOR ATTORNEYS May 5, 1931. A. F. KEANE DISTILLATION SYSTEM Filed April 17, 1926 5 Sheets-Sheet 5 W/ T/VESS y %mmmw I A TTORIVE Y8 ARTHUR F. KEANE, or SYRACUSE, NEW YORK, AssIenoR. ro SEMET-SOLVAY nnernnnn- Patented May 5, 1931 UNITED sr'ras' PATENT OFFICE ING CORPORATION, OF N YORK, N. Y., A CGRPORATIQNOF NEW YORK DISTILLATION sYsTEM Application filed April 17,

The present invention contemplates a process of separating light oils from benzolized wash oil so as to effect a saving of labor, water and steam, to afford a better con rol of the operations than heretofore, and to preheat the feed of benzolized wash oil solely by the vapors from the distilling apparatus.

Another object of the invention is to pro-' vide a structure for effecting the separation of light oils from benzolized wash oils which is so constituted as to incorporate all the units in two operatively connected towers, to eliminate auxiliaries and accessories such as structural steelwork, platforms, piping, preheaters, etc. and thus simplifythe structure materially, to save considerable floor space and height of building, and to provide an apparatus with a low initial cost of manufacture and with small operating costs.

A further object of the invention is to provide a hood structure for the distillation column which has the combined advantages of the single large'cap or hood and the small multiple cap structures, i. e. to provide a multiple effect hood which combines the advantages of a single large hood and a pin rality ofsniall hoods in an integral structure so that the vapors in a still. are distributed uniformly and are forced into intimate contact with the condensate on the plates of the still.

Other features and advantages of the in vention will be made clear by a description of a preferred procedure, and a certain preferred embodiment for carrying said proce-'. dure into effect as illustrated in the accompanying drawings, in which: 7

Fig. 1 is a diagrammatic view of a structure in which my improved process maybe carried out; Y

Fig. 2 is a sectional elevation of column A of Fig. 1;

1926. Serial No. 102,627.

Fig. 3 shows a side elevation of Fig. 2;

Fig. 4% is a fragmentary sectional elevation of Fig. 2, showing the gaugeglasses and condensate drain valves;

Fig. 5 shows a sectional elevation of column B of Fig. 1;

Fig. 6 is a side elevation of Fig. 5, partly broken so asto show details of construction;

Fig. 7 is a fragmentary sectional view, on an enlarged scale, showing one of the connections between a hood and a ring.

Fig. 8 is a top plan view, on an enlarged scale, of one of the rings used in column 13-;

Figs. 9 and 10 are sectional views taken on the lines 99 and 10-10 respectively'of s- 3 Fig. 11 is a top plan view, on an enlarged scale, of one of the hoods used in column 13';

Figs. 12 and 13 are sectional views taken on the lines 1212, and 13-13 respectively of Fig. 11'; 3

Fig. 14 is a fragmentary detail view illustrating the notched weir construction used in the ring shown in Fig 8;

Fig. 15 is a sectional view taken on the line 15l5 of Fig. 14.

Similar characters of reference designate similar parts throughout the accompanying drawings. i I

The invention will be described generally by reference to Fig. 1, in which the letter A designates generally a unitarv column or tower in which a heat exchanger H, a condenser K, a separator S, and a liquid collector C are incorporated. The wash oil used to scrub gasobtained from the destructive distillation of coal extracts or absorbs well-known substances, termed light oils (benzol, toluol, and Xylols), from the gas. After the wash oil contains about 2% of the light oils, it is delivered to the distillation system shown in Fig. 1 through pipe 1. The pipe 1 conducts the aforesaid oil generally known as benzolized wash oil, to the upper coil H-1 of the heat exchanger at a temperature of about 80 C. From the top part of coil H1, the oil flows to the lower part of middle coil H.2 and then out the upper part thereof to lower coil H'3. In this coil, the oil likewise enters at the lower part and leaves at the upper part. While the heat exchanger herein shown consists of three coils or sections, it is obvious that the number may be varied according to the particular conditions and circumstances. The general flow of the oil feed is counter-current to the heating iiuid although a parallel flow is maintained in the individual sections or coils. These coils I'I1, I-I2, I-I3 may be true coils or they may he banks of tubes with headers of w-llmown construction. The heating fluid is the hot vapor coming from the top of the distillation column or tower B through piping to vapor inlet 71. After 172 ng in heat interchange relation with the oil feed so as to heat the latter to about 95 (1, the vapors pass to the condenser K in another portion of the column A, herein shown as the middle portion. The higher boiling components of the vapor condense in the heat interch age section which has dephlegmator plates P and hoods I) incorporated therein. The function of the dephlegmator plates I and hoods D, as is evident, is to efiect a separation of any of the lower boiling components contained in the condensate of higher boiling compoexchanger. Any

nents collected in the lICflL of the lower boiling components condensing in the heat exchanger are vaporized by the vapors coming from the still. The higher boiling components are thus separated from the lower boiling components without the admixture therewith of lower boiling components which constitute the desired product. The lower boiling components are carried in the vapor phase to the upper section K1 of the condenser, then to the middle section Isl-2, and finally to the lower section K3 thereof. In passing through these sections the vapor condenses and collects on the bottom plate Q, of each section, thus forming a pool of condensate having a height determined by an overflow collar L. The condensate flows from one plate to another until it reaches a separator S. Any non-condensable gas is purged from the system in the last condenser section K3 through a purge valve V. In the separator S the condensate separates into two immis cible layers, the upper layer containing the light oils and the lower layer water. The water is drawn off through an adjustable overflow J, the adjustment thereof controlling the height of the plane of division of the layers in separator S, whereas the light oil flows off through an outlet to collectors C. In the present instance, these collectors are shown as the bottom sections of columns A and B connected by pipe 60. This arrangement is very convenient, especially from an operating standpoint.

The adjustable overflow J, as is well. known, consists of an adjusting member 199 and an outer casing usually made of a T member 200, a connecting member 201, and an elbow 202 which is joined to the outlet 12 of the separator. The adjusting member 199 has stem 203 projecting through the cover plate 20% on the top face of the T member 200 and engaging a pipe 205 provided with slots 206 in the upper portion thereof. The pipe 205 makes a liquid-tight joint with diaphragm 207 which is held between the lower flange of the T member 200 and the upper flange of the connecting member 201. By raising or lowering the slotted pipe 205 by means of handle 208 secure to stem 203, the height of slots 206 is raised and lowered, and, thus, the height of th column of liquid in the overflow J is raised or lower l. ,Vhen the height of the li uid column in overflow J is varied, the height of the liquid column in the separator varied proportionally because the two columns must balance each other. In the aforesaid manner the height of the plane of 11 between the liquid layers consti- 1g the liquid column in the separator is controlled in accordance with the adjust ment of the overflow device.

The benzolized wash oil which was pre heated in the heat exchanger H of column A is conducted from section I I3 through oil feed pipe 7 to one of the upper plates P of column B. In the drawing the oil feed is show as introduced at the second top plate of column B which is a distillation column. The oil flows from one plate over the overflow collar L associated with the said plate to a plate below. This llow continues until the oil reaches the bottom of the still. Steam enters the distillation col umn B at the lower portion thereof through a steam inlet 8 and passes upwardly from a lower plate to one above. In passing upwardly the steam strikes the underside of a dome portion 9 of a dephlegmator hood 1) which deflects it towards the periphery of the hood. At and adjacent to the periphery of the hood means are provided to distribute the vapor uniforn'ily through the liquid seal on the plate P1. This feature is more clearly illustrated in a detail view of the dephlegmator hood shown in Figs. 11, 12 and 13 which will be described hereinafter. By this arrangement the vapor passes in intimate contact with the sealing liquid so that the low boiling components are removed therefrom. The vapor (steam and oil fractions) con linue to flow upwardly in contact with liquid on each plate which effects evaporation of the lower boiling components and condensation of the higher boiling components. By controllingthe said fractionation the composition of the vapor may be controlled so that the vapor above the top plate will be composed substantially of all of the light oils absorbed in the wash oil and such steam as was introduced at 8. This of column A.

control also determinesthe composition of the condensate so that the liquid flowing from the bottom plate will be substantially debenzolized wash oil. p

In the operation of my improved distillation apparatus benzolized wash oil is introduced into the top section of the heat interchanger in column A. The oil entering at aboutSO C. passes from the top section the middle one and then to the bottom one, the flow being downward generally, but upward in each individual section. The vapors coming from the top of the still, column B, heat the oilfeed through the medium of the heat interchanger to a temperature of about 95 C. As the temperature of the incoming oil is about 30 *3, there is a heat interchange of about 65 C. This preheat ing is effected solely by the heat of the mixture of light oil vapors and steam from B. After these vapors pass through the dephlegmators in and over the sections of the heat inter-changer H, they flow to'the condenser K positioned in the intermediate portion Fresh water may serve as the condensing medium used in the coils K1, l2, 3-3. The vapor passes in contact with the upper section of the condenser, then with the middle section and lastly with the lower section so that the how is in an upward direction in the sections themselves and in a downward direction from section to section. The condensate collects in each section up to a depth of the overflow collar and then overflows to the section below.-

Thus, a liquidseal is formed at each section through which the vapor must pass so that the said vapor 1s cooled by the condensate as well as by the condenser. As al- 7 separately withdrawn.

Referring now more particularly to Figs. 2, 3, and 4: in which column A is illustrated in detail, this column is an elongated tower which is preferably circular in cross-section. 7 tor C is provided for the light oil. Flanges F-1 and F2 are formed respectively on the closed lower periphery and the open upper periphery of the collector, gauge glass connections G-1 and G2, inlet 11 and outlet 120 (Fig. 1) being positioned in the body of the collector. All the parts ofthe collector are preferably cast integral with it so that a rigid and stron structure is produced. The separator has the same gen eral construction as. the collector so that the lower flange F3 of the formerfits nicely against the upper flange F2 of the latter. At. the lower 1 portion of the separator an outlet 12, is cast integral therewith so that the heavier liquid,

At the base of the tower, the collec in. the present instance water, may be conducted to the adjustableoverfiow J. The lighter liquid, in the present instance light oil, is withdrawn through outlet 10. YVithin the separator and preferably integral with the side thereofa collar Ll is provided which extends from the upper edge of the. separator to near the bottom.

each other and each consists of a ring-shaped body portion it having flanges F5 and F6, at the upper and lower edges thereof. Overflow collars L'-2 and L-3 are cast integral with the ring portion to form over iiew passages diametrically spaced from each other. Thc'collar L2 extends from the lower edge of the section K3 to a pointbelcw the upper edge whereas L3 extends iron the upper edge to a point above the lower edge. The lower extremity of collar L3 joins a deflector E'-1 which extends to the diametricallyopposed collar iii-2. This deflector has a plurality of ports lVl disposed so as to distribute the flow of vapor evenly through a bank of condenser tubes N positioned in any suitable manner above the said deflector and between the said collars. The number 01"- ports M may vary according to the particular circumstances but in the present instance is three. Section K.l is similar to sections K.2 and K-3, except that it has a vapor inlet 112 east in the ring portion just above the lower flange F9 thereof. As section K-l is the upper section of the condenser it has no overflow collar corresponding to L3. The banks of condenser tubes are supported in housings T which are cast integral with the body portions of sections Kl, K2 and K-3 (see Fig.v The housings T-1, T2, and T-3 are closed with cover plates U-1,

U2 and U3 respectively; whereas housings T'l, T5 and T6 have inlet-outlet which separates the sections from each other. Plates Q1,' (D -2' and (l -3 have openings in them to correspond to the overflow passages formed by the overflow collars; It will be observed from Fig. 2 that r the overflow passages are staggered so that a circultous path.1s provided through the condenser.

The condenser is separated from the heat interchanger by a spacer ring Z which has a closed bottom 14 and air holes 13 in the body portion. A plate (lll is interposed between the top of the spacer ring and the bottom of the heat i' iterchanger H. This heat interchanger is c npoz. d of r flanged ring which form heat interchange sec- D-1 are provided in Y-Q. A bank of heat interchange tube;- 1 "ular to the bank of condenser tubes 1 1 l supported in this section. Section l -23 s on Y2 and is similar in all respects to Y2, in that overflow collar L11 cooperates with L1O of section Y---2 and dephlcgmator plate l-- and hood D-3 are placed over the bank of heat interchange tubes N-5. The top section Y at only supports the tube bank N4l and is covered with a header 1G having a vapor outlet 17. This outlet is connected by a pipe 18 to vapor inlet 112 on section K-1 oi the condenser. A chain operat d valve 19 controls the vapor passing through. pipe 18 and heat interchanger H. The tube banks of the heat interchanger like the condenser tube are constructed banks, i. e. housings T-7, T-8, and T9 are closed by covers U7, US and U9 respectively and housings T-10, T-11 and T--1f2 are provided with oil inlet-outlet connections il -10, W11 and W12 respectively. Suitable piping connections 100 and valves 1.01 (Fig. are provided as is well known in the art, for obtaining the proper flow through the tube banks. In the present instance the valves are set so that oil enters through O-1, flows through banks Nl, J. and N-G and leaves through 0-0.

The column is provided with gauge glasses G and drains so that an excessive amount of liquor cannot accumulate at any point in the column. Gaskets of suitable type (not shown) are interposed between the adjacent sections ol the column to term liquidtight joints. The sections may be secured to each other in any well known manner.

The distillation column indicated as column 3 in 1 is shown in greater detail in Figs. 5, 6, and 7. The bottom of this column is provided with a collector C which is similar to the collector of column A. This collector is a casting With a closed bottom 21 with a flange F-12 at its periphery and an open top pr vided with flange F-13. Fitted to the flange top is a flanged spacer ring Z having a closed bottom and an open top. A condensate or steam trap section is pla ed on top of the said ring and is provided with an overflow collar lr-lfl at one side thereof which extends from the top to a point adjacent to the bottom. Cooperatively associated with this condensate section is a trap float and discharge mechanism denoted generally by 22 (Fig. (3) which regulatos automatically the discharge of the condensate. The temperature of the condensate indicated by thermometer 23. A steam imet 8 (Fig. 1) is provided in the upper portion of the condensate section through which steam is introduced in the distillation column proper. This column is cor powd of a plurality of rings 26 superpo on each other. Each ring 26 has a lower oven 2'7 and a diametrically oppose-(i -r overflow collar 28 cast integral ther The lower collar extends from the very l :n to an intermediate point of the ring, whereas the upper collar extends from the very top to an intern'iediate point in said ring lower than the aforesaid interpoint. Below the lower edge of the a plate P extends from one side collar upper to the other where it merges with the collar 2'7. The plate P is substantially symmetrical with an open projection 30 at its center. A cap or hood D is supported over the aforesaid projection by means of spaced lugs 15 which cooperate with hubs 31 of elements resembling inverted crowns 32 (Fig. 7 A bolt passes through lug 15 and hub 31 and cooperates with nut 34: to secure the hood in position. Every ring 26 is flanged top and bottom so that a gasket may be interposed between them to form a liquid-tight joint. The flanges are held together with nuts and bolts as is well known in the art. Adjacent rings are arranged so that the lower overflow collar of the upper ring eoacts with the upper overflow collar of the lower ring to form a condensate passage from plate to plate, the lower end of said passage being closed with a liquid seal. One of the rings in the upper part or the column is provided with a liquid inlet 35 (Fig. 6) through which the preheated benzolized wash oil is introduced by means of pipe 7. The top ring of the column is covering with a header 36 which has a vapor outlet 37 incorporated therein. Through this outlet steam and the vapors carried thereby flow, the steam having entered below the bottom plate and hubbled through the pools of condensate collected on the superposed plates 1?. The condensate flows over the upper edge of the lower overflow collar 27 of one section and through the overflow passage to the section below Where is forms a pool sealing the .tion of this collector.

lower edge of the upper overflow collar 28. Thus, the condensate flows from section to section via the overflowing superposed pools valve 39 is associated with the of the condensate collector in .order' that liquid may be drained from the lower por- The distillation column proper is composed of rings (01' plates P) and dephleg mator hoods (or caps D) which are shown on an enlarged scale in Figs. 8 to 13. These parts are made of metal and are preferably cast as separate integral units. The ring, as shown in. Figs. 8 to. 10, has a cylindrical shaped body portion 40 with projecting flanges 41 at the upper and lower edges thereof. These flanges give rigidity to the ring as well as providing bolt holes 42 through which adjacent ringsare bolted together. The inner faces 43 of the flanges are bossed so as to provide'a smooth surface for gaskets. At the one side of the ring the upper overflow collar 28 is shown extending, around about one-quarter of the periphery of the ring whereby an overflow passage 44 is formed between the inner faces of the ringand the collar. The upper edge 45 of the collar is on a level with the top of the ring, whereas the lower edge 46 is" above the surface of floor plate-29 so as to provide an outlet 47 for the overflow passage 44. The floor plate is substantially symmetrical and has an open projection 30 'at its center." The top 48 of the projection is higher than the lower edge 46 but about on a level with the upper edge 49 of the lower overflow collar 27. From the said top the projection tapers abruptly and then gradually where it joins with the floor plate. The floor plate has a gentle slope towards the periphery of the ring. Beneath the floor plate a plurality of suitable webs 50 are provided to strengthen the structure. Two of these webs are in direct line with webs51 (Fig. 8) of the lower overflow collar. This collar extends around substantially one quarter of the periphery of the ring and is diametrically opposite to the'upper overflow collar. This arrangement insures a circuitous flow of the coi'idensate from one plate to another. The top 49 of collar-27, as noted heretofore,

So is on the same level as the projection 30,

whereas the bottom'52 of the lower overflow collar is on a level with the bottom of the ring. lVebs 53. and 54 (Fig. 8) are provided 1 in overflow passages 44 and 55 respectively so as to reinforce the collars at, the mid-section. It will thus be observed that the diametral disposition of the overflow collars makes it possible with a standard ring to build up a column by staggering alternate sections 180 with respect to each other.

When the rings are so disposed the lower, overflow collar of the upper plate coincldes I with the upper overflow collar of the plate below, while the lower overflow collar of the latter plate coincides with the upper overflow collar of the plate below it. As liquid flows downwardly through the series of superposed rings it collects on the floor plate of each ring to form a pool whose depth is determined by the top 49 of the lower overflow collar. WVhen the depth of the poolexceeds that of the overflow collar,

the liquid flows overtop 49and falls in the overflow passage 55 as a sheet (Fig. 14).

Behind this sheet, in space 81 (Fig. 15),

gases and vapors evolved from the falling liquid collect. In order to prevent an ac cumulation of these gases and vapors in space 81, I incorporate in the overflow collar a notched weir 82. By this construction chimney-like passages 83 are provided at each side of sheet 80 and contiguous to raised portion 84 of the overflow collar. Thus, the gases and vapors collecting behind the fallingsheet of liquid are free to flow upwardly as indicated by the arrows in Fig. 14. The aforesaid pool covers the lower edge 46 of the upper overflow collar as well as the lower edge of the hood so that short circuiting of the upwardly flowing vapor stream is prevented. r i

The hoods which set in the rings are supported by lugs 15. These lugs are bifurcated as shown at 61 (Fig. 8) so that a bolt may be easily slipped in place. The upper face of each lug coacts, as explained heretofore, with a hub 31 supported in each of the inverted crowns 32 by a spider 56-. The inverted crowns82 (Fig. 11) are similar to the inverted crowns 32 ex opt for the spiders and hubs. All of the inverted crowns are open from top to bottom and have the shape of inverted truncated cones each of which terminates in a serrated edge 57 (Fig. 12).

These serrations form a multiplicity of orifices through which the upwardly flowing vapors must pass... The outer edge 58 (Fig. 11) of the dephlegmator hood is also provided-with serrations. The vapors are dirooted to the serrated edges by the dome portion 9 (Fig. 12) of the dephlegmator hood in which reinforcing webs 60 (Fig. 13) aid in effecting a uniform: distribution of said vapors. Inorder to facilitate therehole 59 is provided at'the top of dome 9.

The assembly and arrangement of the aforesaid parts in the distillation apparatus as well as their mode of functioning and operation has been described heretofore, and, therefore, need not be repeated.

I claim:

1. In a steam distillation apparatus the combination of a steam distillation column containing a plurality of similar ring sections provided with plates and overflow collars, the alternate ones of which are staggered 180 with respect to once other forming a circuitous path via cooperating overflow collars of adjoining plates, a hood having a multiplicity of inverted crown-like elements therein supported on each of said ring sections, with a unitary structure composed of superposed cooperating ring and plate sections constituting a heat interchanger for liquid feed going to and vapor product coming from the said distillation column, a condenser for condensing the said vapor after it has passed through said heat interchanger, and a separator in which the condensate from the aforesaid step separates into two layers so as to permit water contained in the upper of said two layers and product to be withdrawn continuously and separately.

2. In a distillation apparatus, the combination of a still with a unitary structure containing cooper ting elements superposed upon each other and constituting a heat exchanger operatively associated with said still and adapted to preheat the liquid feed going to the still and to cool the vapors coming from the still, a condenser receiving the vapors from said heat exchanger, and a separator into which the condensate from said condenser flows and separates into layers, said separator having means associated therewith whereby the height of the plane of division of said layers may be controlled in order that the lower layer of condensate and the upper layer of condensate may be withdrawn through their respective outlets.

3. In a distillation apparatus, the combination of a still with a unitary structure containing cooperating elements superposed upon each other and constituting a heat exchanger operatively associated with said still and adapted to preheat the liquid feed going to the still and to cool the vapors coming from the still, a condenser receiving the vapors from said heat exchanger, a separator into which the condensate from said condenser flows and separates into layers, said separator having means associated therewith whereby the height of the plane of division of said layers may be controlled in order that the lower layer of condensate and the upper layer of condensate may be withdrawn through their respective outlets, and a collector connected to the said outlet for the upper layer.

4. An integral dephlegmator hood for distillation columns comprising a main domeshaped portion having the lower edge thereof formed to facilitate and to insure intimate contact between a vapor and a liquid, and a plurality of inverted crown-like elements disposed in said main portion, each of said inverted crown-like elements having outlet passages at the lower end thereof which increase the available vapor outlet area.

5. An integral dephlegmator hood for distillation columns comprising a main domeshaped portion having the lower edge there of formed to facilitate and to insure intimate contact between a vapor and a liquid, and a plurality of inverted crown-like elements disposed uniformly in said main por tion about the center thereof, each of said inverted crown-like elements having outlet passages at the lower end thereof which increase the available vapor outlet area.

6. An integral. dephlegmator hood for disillation columns comprising a main domeshaped portion having the lower edge there of formed to facilitate and to insure intimate contact between a vapor and a liquid, a plurality of inverted crown-like elements disposed in said main portion, each of said inverted crown-like elements having outlet passages at the lower end thereof which increase the available vapor outlet area, and means incorporated in some of the inverted crown-like elements for cooperating with a support.

7. A hood structure for a distilling apparatus comprising a main dome-shaped portion having a serrated periphery, and a plurality of inverted crown-like elements integral with said main portion, each of said elements having a lower serrated edge.

8. A hood structure for a distilling apparatus comprising a main dome-shaped portion having a serrated periphery, and a plurality of inverted'crown-like elements integral with and disposed uniformly in said main portion, each of said elements having a lower serrated edge.

9. A ring section for a distillation column comprising a substantially symmetrical body portion; a floor plate within said body portion extending from the inner periphery thereof to the center and terminating adjacent to the center in an open projection; a lower overflow collar having a notched weir incorporated therein positioned adjacent the inner periphery of said body portion, the upper edge of said weir being at a height not higher than the said open projection and the lower edge being on a level. with the bottom of said body portion; and an upper overflow collar positioned substantially diametrically opposite said lowor overflow collar on the inner periphery of said body portion, the lower edge of the said upper overflow collar being at a height lower than the said open projection and the upper edge being about on the level with the top of said body portion. 1

10. A combination. unitary structure for distillation systems comprising a plurality of superposed ring-like sections constituting a heat interchanger, a condenser, and a separator; the bottom section being the separator for condensate composed of two immiscible liquids and having a collar associated therewith, a collar in the section above to cooperate with the aforesaid collar of the bottom section to form an overflow passage to said separator; the section having the collar associated with the collar in the separator being the lowermost one of the condenser located above said separator and having another collar diametrically opposite the collar in the lowermost section of the condenser, vapor deflector extending between the diametrically opposite collars in the con denser, and a bank of condenser tubes positioned above'said vapor deflector; the aforesaid condenser being provided with two other sections substantially similar to the first-named condenser section, the uppermost section having a vapor inlet; and the unitsection above said condenser being the heatinterchanger for preheating liquid feed to a still, the said interchanger being divided into a plurality of 'operatively connected compartments, the lower of said compartm nts having a vapor in let for vapors coming from a still and the upper a vapor outlet-connected to the inlet of the condenser.

11. A process for treating benzolized wash-oil, which comprises the following stages: first stage: preheating the benzolized wash-oil to about 95 C. by the means set forth in the fourth stage and thence introducing the thus preheated oil directly and without additional thermal treatment to the second stage; second stage: forming a series of superposed shallow pools of preheated benzolized wash-oil, bubbling steam from a central entrance for each pool outwardly through the pool to a series of orifices, thereby separating benzol and similar light oils from the wash-oil and carrying them along with the steam while allowing concentration of wash-oil in the pools and overflowing of the pools downwardly; third stage: removing substantially pure wash-oil from the lowest pool; fourth stage passing the steam and light oil vapor inheat exchange relationship with the benzolized wash-oil to cause the preheating mentioned in the first stage and simultaneouslytherewith, during said passage-in heat-exchange relation as between the gaseous steam-oil vapor stream on the one hand and the liquid stream of benzolized wash-oil on the other, causing localized condensation of a part of the vapors against the Walls through which the aforesaid heat exchange is efiected, collecting said condensate and passing the steam :and oil vapor therethrough to re- 12. Apparatus for separating light oils frein benzolized wash-oil, which comprises a tower composed of a plurality of chambers, one of said chambers having a series of superposed preheating coils therein arranged to rec-ive benzolized wash-oiland to pass it from the chamber in a preheated condition, still having a series of superposed rings and hoods arranged to hold shallow pools of oil therein, a steam inlet admitting steam into the still and allowing it to pass from one ring and hood to another through the pools, a conduit leading from above the uppermost hood to a point below the lowermost preheating coil to permitsteam and light oil to come into heat-exchange relation successively with the wash-oil in the coils, condenser coils located in a lower chamber of the tower, a conduit leading from above the upper preheating coil to the chamber containing the condenser coilsanda separator for separating the condensed water from the condensed light oil sald separator being positioned in a third chamber of the tower below the chamber containing the condenser coils. I

13. Apparatus for separating li ht oils from'benzolized washsoil, which comprises a tower composed of a plurality of chambers, one of said chambers having a series of superposed preheating coils therein arranged to receive benzoliZedwash-oil and to pass it from the chamber in a preheated condition a'still havin a series of su er osed a e P P rings and hoods arran ed to hold shallow pools of oil therein, a steam 1nlet admitting steam into the still and allowing'it to pass from one ring and hood to another through the pools, a conduit leading from abovethe uppermost hood to a point below the lowermost preheating coil to permit steam and light oil to come into heat-exchange relation successively with the wash-oil in the coils,

condenser coils located in a lower chamber of the tower, a conduit leading from above the upper preheating coil to the chamber containing the condenser coils, a separator for separating the condensed water from the condensed light oil, a collector for said light oil, said separator and said collector being positioned respectivel in superposed chambers of the tower be ow the chamber containing the condenser coils and another collector connected with, said first collector, positioned under the still.

14. In a distilling apparatus, a hood structure comprising a dome having a series of teeth around its lower edge and a series of inverted c own-like elements cast on the lower face of said dome, each of said inverted crown-like elements having its lower edge provided with a series of teeth.

15. In a distillation apparatus the combination of a still with a unitary structure containing a heat exchanger and a condenser, said struct" e being operatively associated with said s said heat exchanger arranged to receive liquid feed going to and vapor coming from the still, and dephlegmator means within said heat exchanger to effect a separation by vaporization, of any lower boiling components from the condensate of higher boiling components formed in said exchan er, and said condenser adapted to condense the vapor received from said heat exchanger.

16. In a. distillation apparatus the combination of a still with a unitary structure containing a heat exchanger, a condenser and a separator, said structure being operatively associated with said still, said heat exchanger arranged to receive liquid feed going to and vapor coming from the still and dephlegmater means within said heat exchanger to effect a separation by vaporization of any lower boiling components from the condensate of higher boiling components formed in said exchanger, said condenser adapted to condense theyapor received from said heat exchanger, and said separator arranged to receive the condensate from said condenser and permit the separation of said condensate into two layers, the upper layer being the desired fraction of light oil.

17. A process for treating benzolized washoil which comprises the following stages: first stage: preheating the benzolized washoil in the manner set forth in the fourth stage and then introducing the thus preheated oil to the second stage; second stage: forming a series of superposed shallow pools of preheated benzolized waslroil, bubbling steam from a central entrance for each pool. outwardly through the pool to series of orifices, thereby separating benzol and similar light oils from the wash-oil and carrying them along with the steam while allowing concentration of wash-oil in the pools and overllowinoof the pools downwardly; third stage: removing substantially pure wash-oil from the lowest pool; "fourth stage: passing the steam and oil vapor resulting from the third stage in heat-exchange relation with benzolized wash-oil to cau e the preheating of said oil as mentioned in the first stage and to cause simultaneously the cooling of said vapor and steam to condense therefrom higher boiling components and simultaneously vaporizing lower boiling components in said condensate by causing said steam and light oil vapor to pass through said condensate during its said passage about the benzolized wash-oil; fifth stage: p, sing the lig 1t oil vapor and steam, on lGlL'\llL and as cooled by the fourth stage, into heat-exchange relation with a condensing medium d condensing the vapor and steam; sixth gc: separating the light oil from the water.

18. In a distillation apparatus, the combination 01" a still with aheat exchanger separate from and operatively connected thereto, said heat exchanger being built up of a plurality of like sections, each section containing a floor plate provided with an overflow collar over which liquid condensate fiows from the plate in one section to the floor plate in the sect-ion below, and coils in each section for receiving liquid teed going to said still, the vapors from said still passing through the condensate formed in the exchanger to effect separation by vaporization oi any lower boiling components from the condensate of higher boiling components, said vapors passing through said exchanger in heat exchange relation with the liquid feed in the coils going to the still.

19. In a distillation apparatus, the combination of a still with a heat exchanger separate from and operatively connected thereto arranged to receive liquid teed going to and vapor coming from the still, said heat exchanger being built up of a plurality of like sections, each section containing a floor plate provided with an overflow collar over which liquid condensate flows from the plate in one section to the floor plate in the section below, and coils in each section for receivin liquid feed going to said still, the coils of each section being interconnected, said coils being arranged so that the flow through the coils in each section occurs in co-current relation with the vapors passing through the section, the flow of liquid from the coils of one section to another being countercurrent to the flow of vapors through the heat exchanger, the vapors from said still passing through the condensate in the exchanger to effect a separation by vaporization of any lower boiling components from the condensate of higher boiling com ponents in the heat exchanger.

In testimony whereof I have hereunto set my hand.

ARTHUR F. KEANE. 

